A profile milling machine has a copying structure provided with a contact rod having a semi-spherical surface at the tip end of the contact rod. A tip end of an end mill cutter is likewise formed in a semi-spherical surface having the same radius and with high accuracy. Thus, it was hitherto impossible to manufacture a product with high accuracy.
It is an object of the present invention to provide a ball end mill cutter capable of manufacturing a workpiece adapted to mass-production with small size and extremely high accuracy.
A conventional ball end mill cutter will not be manufactured in a small size compared with that having a blade integrally mounted with a body.
Another ball end mill cutter having a blade integrally mounted with a body is well known. A cutting edge thereof is not smoothly provided at a junction portion of a cylindrical body and a semi-spherical blade mounted on the body. When a workpiece is cut with use of this ball end mill cutter, there remains a trace of the junction portion on the workpiece, thereby causing the workpiece to be inferiorly finished and making it difficult to proceed to the next manufacturing step so that it takes time and labor to manufacture the workpiece and manufacture is only with limited accuracy.